Raw data status filepath removal

Modifications to the raw data object:
 - Added a status to the raw data, to know when the files have been uploaded or they are being uploaded.
 - Added a function to remove all the filepaths associated from the RawData `clear_filepaths`
 - Added a function to remove a filepath from the RawData `remove_filepath`

Adds the needed bits for #548 
The check above for whether the file is used will not apply if the specified path is a directory, right? So this could be dangerous. Before removing a directory, you might have to check recursively using `walk` whether or not any of the files *in* the directory are being used?